Jackson JSON Processor Home
Inspired by the quality and variety of XML tooling available for the Java platform (StAX, JAXB, etc.), the Jackson is a multi-purpose Java library for processing JSON data format. Jackson aims to be the best possible combination of fast, correct, lightweight, and ergonomic for developers.
Introduction
First things first:
Jackson Tutorial gives you reasonable overview of basic usage
Licensing page outlines what Open Source licenses are used with Jackson (ASL, LGPL)
Jackson FAQ covers various other aspects, including common usage cases.
Jackson Users Group is the place to learn even more about Jackson community, things other users do and share, as well as future development plans.
Testimonials
After introduction, you may want to know who is already using Jackson for production work:
Sampling of current users gives an idea of Jackson adoption
Get it!
And then it may be time to check Jackson out:
Download page has all the artifacts (jars, sources) you need; specifically, 1.8 which is the latest official version.
Project
Jackson project page at Codehaus has more day-to-day information about development process, and active Open Source developers working on Jackson
In addition to the core project, there are numerous extensions that provide additional functionality and support for third-party libraries and data types:
Jackson Modules are pluggable components that extend out-of-box functionality to support additional data types or JVM languages. Check out Module projects page for complete listing of known module projects.
There are also projects that offer support for alternative data formats beyond JSON (like XML, BSON); see Jackson outside of JSON page to learn more.
More to Learn
And if (when!) this all looks good, there is plenty more to learn:
Jackson Documentation has plenty more to guide you through more advance usage
TODO covers areas that could use contributions from new contributors...
Future plans: work towards version 2.0 (big backwards-incompatible changes -- but happily co-exists with Jackson 1.x)
Other
Beyond these first steps, you may want to investigate these resources:
CowTalk Blog has blog entries related to Jackson usage, development.